(1) Field of the Invention
This invention relates to the treatment of semiconductor wafers with HMDS vapor to improve resist adhesion. More particularly the invention relates to a method and apparatus for purging the pipes of the system after wafer treatment to prevent HMDS condensation in the pipes.
(2) Description of the Related Art
U.S. Pat. No. 5,501,870 to Shiraishi et al. and U.S. Pat. No. 5,401,316 to Shiraishi et al. describe apparatus and methods for treating semiconductor wafers with HMDS vapor to improve resist adhesion but do not describe methods for purging the pipes in the apparatus to prevent HMDS condensation.
U.S. Pat. No. 5,505,781 to Omori et al. describes an apparatus for treating semiconductor wafers with HMDS vapor to improve resist adhesion. A HMDS liquid and vapor delivery system is described but automatic purging of the pipes in the apparatus to prevent HMDS condensation is not described.
This Patent Application describes an apparatus and method for treating semiconductor wafers with HMDS vapor wherein HMDS vapor is purged from the pipes after the wafer treatment is complete. The purging of the pipes prevents HMDS condensation and contamination of the HMDS supply.